304 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



todes protruding their heads two or three centimeters from the mucous membrane, into which they 

 would rapidly withdraw when touched. It was then noticed that they were in the vicinity of swollen 

 masses, apparently cysts in the stomach wall. An examination of one of these revealed a large nenia 

 todc coiled up in this living nest, not encysted, but able to leave the nest whenever occasion 

 demanded. The mucous membrane was dissected away from one of these worms, showing that it was 

 coiled up in the submucosa (tig. 116). Around it, for a space some 3 cm. square, the tissues were highly 

 inllamed and lilled with extravasated blood. Pus was also observed in at least one of these cavities, 

 occupied by a nematodc. 



Although the worms arc not completely encysted there is evidently a considerable accumulation 

 of connective tissues in the subiuncosa in the vicinity of these nests. Communication seems to be 

 maintained by the worm between the crypt and the lumen of the stomach. 



This habit of making a nest for itself in the stomach wall of ite host is certainly an unusual one, 

 and for the comfort of a groaning and travailing creation it is to be hoped that there are few parallel 

 cases iu nature. 



Ichthyonema sanguineum Rudolph! ( ?). 



[Plate 43, figs. 120-121, TJ. S. N. M. No. 6535.] 



A single example of a blood-red iieniatode from the inside of the cheek of a llounder ( Paralichthys 

 deutatiix), where it was partly embedded, appears to be near to or identical with Ichthyonema sanyuin- 

 ciini. The flesh of the host was much inflamed in the vicinity of the worm. The specimen proved 

 to be a female and was crowded with young. The latter are very minute, one end blunt, the other 

 exceedingly attenuate. I have not examined the young of this genus with great care, although I have 

 collected them at different times. In my notes I hud that I have been calling the attenuate end the 

 anterior, but since this is contrary to authorities on this subject I have probably been in error. My 

 notes made at the time of collecting would appear to state that the progressive motion of these worms 

 is in the direction of the smaller end. 



The body of the adult is linear and narrows rather abruptly at the anterior end. The head 

 bears four broad lobes or flat surfaces, each of which carries two papilla;. The oesophagus, at first 

 slender, enlarges gradually to a point a little behind the middle of its length, whence it maintains 

 about the same diameter to its rounded base. The -intestine at its beginning is but little larger in 

 diameter than the (esophagus. A slender anterior portion of the ovary is seen lying beside and across 

 the (i-sophagus. The uterus is very spacious. The sections of the anterior end Avhich were made 

 show considerable variation in the relative dimensions of uterus and intestine. In most of the sec- 

 tions the uterus occupies far the greater part of the body cavity, and is filled with the young, of 

 which there is an immense number. Near the posterior end the diameter increases and the posterior 

 end is bluntly rounded. 



The following dimensions, in millimeters, are of the preserved specimen: Length 30: diameter 

 of head 0.23; length of ujsophagus 1.14; diameter of cusophagus, anterior 0.1, posterior 0.17; greatest 

 diameter (specimen somewhat flattened) 1; diameter near posterior end 0.85. 



EXPLANATION OF PLATES. 



a. Acetabulum. i. Intestine. t. Testis. 



c. Cirrus. o. Ovary. u. Uterus. 



e. Ova. p. Prostate gland. vd. Vas deferens. 



cp. Cirrus pouch. ph. Pharynx. vy. Vitelline gland. 



ex. Excretory vessel. ar. Seminal receptacle. yd. Vitelliue duct. 



g. Genital aperture. sv. Seminal vesicle. 



The figures have been reduced about one-fifth. 



